With the rapid development of wireless communication technology, the continuous evolution of wireless protocol has highlighted the importance of mode-mixing base stations in the future market, mainly as follows: wireless network is developing from 2G to 3G and the Global System For Mobile Communication (GSM) network needs to realize the smooth transition to 3G network, and therefore base stations are required to support GSM systems at the very beginning. In addition, the base stations must maintain the capability for the carriers from GSM to the Universal Mobile Telecommunications System (UMTS) to coexist in an operator's frequency in the process of switching networks and the capability of mixing modes in different systems while switching completely to UMTS. The continuous evolution of 3G protocols also requires wireless base stations to mix modes in different modes, for example, base stations for the Wideband Code Division Multiple Access (WCDMA) needs to evolve toward a Long Term Evolution (LTE) amid protocol evolution. In addition, base stations may also need to switch between different standards. For example, CDMA2000 base stations need to smoothly switch to WCDMA or directly upgrade to LTE. FIG. 1 shows the processing of intermediate frequency (IF) signals. As shown in FIG. 1, most prior-art IF signal processing chips support the signal processing system in a single communication mode only, and does not have the ability to simultaneously support multiple bandwidth carrier signals.
The prior art which supports the IF signal processing system in a single communication mode has the following shortcomings:                Each stage of filters, i.e. signal processors, has a fixed number of shift registers, so the supported maximum orders of the filters are fixed;        each stage of filters has a fixed number of multipliers, and therefore, the supported maximum processing bandwidth of the filters is fixed;        the multiply-adding and caching resources cannot be shared among the filters, i.e. the multiply-adding and caching resources of one stage of filters cannot be used by other filters; and        the change of link relationships, such as forward and backward, the change of link parameters, such as filter order and carrier number, or the change of carrier rate may cause redesign of links, and therefore, the universality of the system is poor.        